Magnetic data storage media, such as magnetic tape and magnetic disks, are commonly used for storage and retrieval of data. The magnetic storage media generally have a series of transitions between different magnetized regions. The different magnetized regions may encode a series of bits that represent a value of “0” or “1”. The magnetically oriented regions may be aligned on data tracks that divide the magnetic medium. In order to subsequently store data on the magnetic storage medium, a recording head of a magnetic drive, such as a tape drive or disk drive, encodes data by selectively orienting various magnetic regions on the medium. A read head of a magnetic drive may later detect the regions, and the drive can interpret the detected regions to retrieve the data.
Magnetic storage media such as magnetic tape and disks are typically manufactured by coating one or more magnetic layers on a substrate and then drying the resultant coating to form a magnetic film. One or more intermediate layers may reside between the magnetic layer and the substrate. For example, an intermediate layer known as an underlayer or sublayer may be coated over the substrate before coating a magnetic layer. An underlayer may be coated in a sequential process that is substantially simultaneous with the coating of the magnetic layer. A backing layer may be further attached to the substrate to provide mechanical and performance benefits. Together the various layers create the structure of a magnetic storage medium.
Larger data storage demands and technological advancements have led to increased data storage densities. The amount of data that a magnetic drive can store on a magnetic layer of a magnetic data storage medium is determined by the areal density with which bits of data are stored on the medium and the area of the magnetic layer of the medium. In general, higher storage density can be achieved by increasing the number of magnetic particles in a magnetic layer, adding additional magnetic layers, using thinner layers, or providing magnetic particles capable of increased density. Higher density data storage can improve data storage capacities or reduce the size of magnetic drives storing the same amount of data.